Often the fighting was in open trenches, warmed by steamer fires.

These kinds of bunkers give people fighting better protection than an open trench.

This is far safer than open trenches if a vehicle should run off the highway.

Every night, the women worked together to dig open trenches.

But the quality of sound was a bit different within a shelter than in an open trench.

Then it went down into an open trench, and there wasn't anything to see.

They examine open trenches to look for clues about past earthquakes.

An open trench, even if lined with concrete, could be hazardous.

Instead of boring through rock and soil, an open trench was cut.

The five open trenches beside it were outlined with standing waves that looked like the result of the same process.